A variety of wounds are now being treated using negative pressure wound therapy. However, many of these wounds have characteristics that limit the effectiveness of existing techniques. Wound dehiscence, in which the wound margins have substantial separation, pose significant problems in reapproximation of tissue and wound drainage. For example, there are a large number of patients undergoing amputations in the United States every year. These have different causes including traumatic injury, peripheral vascular disease, diabetes mellitus and chronic venous insufficiency. Patients with diabetic conditions, for example, often suffer from restricted blood flow that can lead to tissue necrosis at the body extremities. For patients with severe symptoms, a transmetatarsal amputation (TMA) may be recommended to remove afflicted tissue while still salvaging a portion of the foot. In many cases, a transtibial or below-knee amputation (BKA) must be performed. An important factor in the recovery of a patient from amputation is how quickly the wound can be closed. Because the gap between tissue margins can be large, the wound is manually closed by suturing. There must be ongoing attention to prevent complications such as infection, wound dehiscence, and/or ischemia. The use of an immediate post-operative prosthesis (IPOP) is commonly employed to reduce the recovery period for BKA procedures, for example.
Other examples of wounds that can be difficult to achieve approximation of the wound margins can include ulcers in which the wound opening is surrounded by tissue overlying a cavity. The undermining of the tissue surrounding the wound opening can often present problems in drainage and rapid wound closure. There are also open wounds that can occur in both the extremities and the abdominal regions in which the wound margins must rotate over a substantial distance, often up to several centimeters or more, to achieve approximation of the margins. Thus a continuing need exists for improvements in wound closure devices and methods.